Some powered systems such as, but not limited to, off-highway vehicles, marine diesel powered propulsion plants, stationary powered system, transport vehicles such as transport buses, agricultural vehicles, and rail vehicle systems or trains, are typically powered by one or more power units, or power generating units. With respect to rail vehicle systems, a power unit is usually a part of at least one locomotive powered by at least one internal combustion engine and the train further includes a plurality of rail cars, such as freight cars. Usually more than one locomotive is provided wherein the locomotives are considered a locomotive consist. Locomotives are complex systems with numerous subsystems, with each subsystem being interdependent on other subsystems.
An operator is usually aboard a locomotive to insure the proper operation of the locomotive, and when there is a locomotive consist, the operator is usually aboard a lead locomotive. A locomotive consist is a group of locomotives that operate together in operating a train. In addition to ensuring proper operations of the locomotive, or locomotive consist, the operator also is responsible for determining operating speeds of the train and forces within the train that the locomotives are part of To perform this function, the operator generally must have extensive experience with operating the locomotive and various trains over the specified terrain. This knowledge is needed to comply with prescribeable operating parameters, such as speeds, emissions and the like that may vary with the train location along the track. Moreover, the operator is also responsible for assuring in-train forces remain within acceptable limits.
In marine applications, an operator is usually aboard a marine vehicle to insure the proper operation of the vessel, and when there is a vessel consist, the lead operator is usually aboard a lead vessel. As with the locomotive example cited above, a vessel consist is a group of vessels that operate together in operating a combined mission. In addition to ensuring proper operations of the vessel, or vessel consist, the lead operator also is responsible for determining operating speeds of the consist and forces within the consist that the vessels are part of. To perform this function, the operator generally must have extensive experience with operating the vessel and various consists over the specified waterway or mission. This knowledge is needed to comply with prescribeable operating speeds and other mission parameters that may vary with the vessel location along the mission. Moreover, the operator is also responsible for assuring mission forces and location remain within acceptable limits.
In the case of multiple power powered systems, which by way of example and limitation, may reside on a single vessel, power plant or vehicle or power plant sets, an operator is usually in command of the overall system to insure the proper operation of the system, and when there is a system consist, the operator is usually aboard a lead system. Defined generally, a system consist is a group of powered systems that operate together in meeting a mission. In addition to ensuring proper operations of the single system, or system consist, the operator also is responsible for determining operating parameters of the system set and forces within the set that the system are part of. To perform this function, the operator generally must have extensive experience with operating the system and various sets over the specified space and mission. This knowledge is needed to comply with prescribeable operating parameters and speeds that may vary with the system set location along the route. Moreover, the operator is also responsible for assuring in-set forces remain within acceptable limits.
Based on a particular train mission, when building a train, it is common practice to provide a range of locomotives in the train make-up to power the train, based in part on available locomotives with varied power and run trip mission history. This typically leads to a large variation of locomotive power available for an individual train. Additionally, for critical trains, such as Z-trains, backup power, typically backup locomotives, is typically provided to cover an event of equipment failure, and to ensure the train reaches its destination on time.
Furthermore, when building a train, locomotive emission outputs are usually determined by establishing a weighted average for total emission output based on the locomotives in the train while the train is in idle. These averages are expected to be below a certain emission output when the train is in idle. Typically, however, there is no further determination made regarding the actual emission output while the train is in idle. Thus, though established calculation methods may suggest that the emission output is acceptable, in actuality the locomotive may be emitting more emissions than calculated.
When operating a train, train operators typically call for the same notch settings when operating the train, which in turn may lead to a large variation in fuel consumption and/or emission output, such as, but not limited to, Nox, CO2, etc., depending on a number of locomotives powering the train. Thus, the operator usually cannot operate the locomotives so that the fuel consumption is minimized and emission output is minimized for each trip since the size and loading of trains vary, and locomotives and their power availability may vary by model type.
With respect to a locomotive, however, even with knowledge to assure safe operation, the operator cannot usually operate the locomotive so that the fuel consumption and emissions is minimized for each trip. For example, other factors that must be considered may include emission output, operator's environmental conditions like noise/vibration, a weighted combination of fuel consumption and emissions output, etc. This is difficult to do since, as an example, the size and loading of trains vary, locomotives and their fuel/emissions characteristics are different, and weather and traffic conditions vary.
A train owner usually owns a plurality of trains wherein the trains operate over a network of railroad tracks. Because of the integration of multiple trains running concurrently within the network of railroad tracks, wherein scheduling issues must also be considered with respect to train operations, train owners would benefit from a way to improve fuel efficiency and/or emission output so as to save on overall fuel consumption, while reducing emission output of multiple trains while meeting mission trip time constraints.
When planning a mission that may be performed autonomously, which includes little to no input from the operator, planning the mission may be difficult if the planning is not robust enough to accept various user inputs. In standard optimization theory, constraints are used to restrict the system to behave in a given way. However, this can lead to situations where a physically reasonable problem is rendered unsolvable because it is not strictly feasible given the mathematical constraints specified on the optimization problem. This can cause the whole optimization to fail. For example, with respect to a rail vehicle, to constrain the rail vehicle notch to behave smoothly, a rate limit may be imposed on the notch. However in exceptional cases, such as but not limited to abrupt grade variations, it may be impossible to satisfy this constraint while avoiding over speeding and/or stalling. In another example if a certain speed is imposed but the rail vehicle does not have sufficient power to reach the specified speed, the optimization may fail.
Another concern with planning the mission occurs when re-plan missions are identified to replace a currently used mission plan. A mission planner typically uses algorithms, and/or computer-readable instructions executable by a processor that are computationally complex and require a high percentage of computer processing utilization. Therefore processing time is a concern, especially when multiple re-plans are identified. When re-plans are identified they are usually cued to be implemented in the order they are prepared. Doing so may result in more urgent re-plans not occurring in a timely fashion. Furthermore, there may be times during a mission when implementing a re-plan mission is not preferred.
Owners and/or operators of rail vehicles, off-highway vehicles, marine powered propulsion plants, transportation vehicles, agricultural vehicles, and/or stationary powered systems would appreciate the financial and operational benefits realized when these powered system produce optimized fuel efficiency, emission output, fleet efficiency, and mission parameter performance so as to save on overall fuel consumption while reducing emission output and meeting operating constraints, such as but not limited to mission time constraints, where re-planning of a mission plan is accomplished to reduce processor utilization and to insure higher priority re-plans are implemented first.
Some existing energy management systems can be used to control operations of vehicle systems during a trip to “optimize” performance of the vehicle systems. For example, Trip Optimizer™ provided by General Electric Company can be used to automatically control or direct an operator to control throttles of locomotives in a rail vehicle system to assist in keeping the rail vehicle systems on schedule while reducing fuel consumption and/or emission generation (relative to operating the locomotives without using Trip Optimizer™) These types of energy management systems can take into account factors such as length of the rail vehicle system, weight of the rail vehicle system, grade of the route being traveled upon, conditions of the route, weather conditions, and performance characteristics of the vehicles. The energy management systems create trip profiles or trip plans that reduce braking and can reduce the fuel consumed and/or emissions generated.
During travel according to a trip plan, various factors may cause the vehicle system to be unable to continue traveling according to the trip plan. For example, deteriorating health of a propulsion-generating vehicle in the vehicle system, damage to the vehicle system, damage to a route being traveled upon, adverse weather conditions, operator action (e.g., manual control) of the vehicle system, or the like, can cause the vehicle system to fall behind or otherwise be unable to follow the trip plan.
Some known systems and methods can “re-plan” the trip plan by revising the trip plan to account for the vehicle system falling behind the prior trip plan. But, these re-plans may generate a transitional plan that causes operations of the vehicle system to rapidly increase to return to operating according to the prior trip plan. Or, these re-plans can create new trip plans that begin with operational settings that are significantly different from the prior trip plan. As a result, the vehicle system may need to rapidly increase output in order to attempt to travel according to the revised trip plan. Either of these scenarios can cause the vehicle systems to significantly increase the amount of fuel consumed and/or emissions generated, in contradiction to the goals sought to be achieved by the trip plans.
A vehicle system may include one or more powered vehicles that may be mechanically linked (directly or indirectly) to non-powered vehicles. The powered and non-powered vehicles of the vehicle system may travel as a group along a designated route. In cases where the vehicle system includes multiple powered vehicles, the vehicle system may coordinate operations of the powered vehicles to move the vehicle system. For example, a rail vehicle system may include a powered unit consist that has one or more powered units mechanically coupled to one or more non-powered rail cars. Vehicles in a consist may include a lead powered unit and one or more remote powered units and/or trail powered units. (Remote powered units are those that are spaced apart from the lead powered unit by one or more non-powered vehicles. Trail powered units are those that are in the same powered unit consist as the lead powered unit, and thereby not spaced apart from the lead powered unit by one or more non-powered rail vehicles, but that are subordinate to control by the lead powered unit.) The lead vehicle may control operation of one or more remote vehicles.
Various control actions for all or a portion of a mission or trip may be planned in advance. The control actions may be planned in advance using expected values of parameters, for example values expected based on train makeup and/or locomotive type. However, factors beyond the control and/or knowledge of a planner may result in characteristics of the vehicle system, such as mass, horsepower, or braking capability, among others, being different than the expected values. The difference between the expected and actual values may cause a calculated plan to be inaccurate and/or inefficient due to being calculated using incorrect values. Such inaccuracy may cause customer dissatisfaction and potential losses in fuel savings.
A transportation network for powered vehicles includes interconnected routes on which powered vehicles travel between locations. The routes connect to one another at intersections, which may also be referred to junctions, interchanges, crossovers, or turnouts. Powered vehicles can be capable of changing routes at such intersections. By way of one example, a transportation network may be formed from interconnected railroad tracks that are configured to have rail vehicle systems traveling along the tracks. At some intersections, a rail vehicle system (e.g., one or more locomotives optionally coupled with one or more rail cars) may be guided by a turnout switch to change from one route to another route.
Some powered vehicle systems may operate according to a trip or mission plan (also referred to as operating plan) while traveling along a route. The trip plan may be used, for example, to control operation of the vehicle system so that the vehicle system achieves or operates within certain parameters during the trip. These parameters can include fuel usage, which can be a significant expense in operating a vehicle system, and regulations that limit operation of the vehicle system in some manner. For example, regulations may require that the vehicle system does not exceed speed limits for certain segments of a route, exceed noise for certain areas or regions, or exceed national or regional fuel emission standards. Accordingly, the trip plan may be configured to operate the vehicle system in a manner that optimizes one or more parameters (e.g., fuel consumption) while also satisfying other conditions (e.g., speed limits, emissions, arrival time). With respect to a rail vehicle system, the trip plan may be used to automatically control tractive effort and/or braking of the rail vehicle system to arrive at a destination within a designated time while also minimizing the fuel consumption and/or emissions of the trip.
During operation of a vehicle system, however, the vehicle system may receive instructions or be commanded by an operator to deviate from the current trip plan. For instance, when approaching an intersection between two or more tracks, the operator (e.g., engineer) of a rail vehicle system may be notified by a divergence signal that the rail vehicle system should or will change to another track at a turnout switch. But the alternative track may not be part of the original route that was used to determine the trip plan. Presently, the operator may remove the rail vehicle system from automatic control and manually control the vehicle system as rail vehicle system transitions from one track to the next. Some time after the vehicle system changes to a different track, a new trip plan may be generated, which may take a significant period of time to generate. During this manual operation and delay for trip plan generation, however, the vehicle system may lose fuel saving opportunities and/or time in which the vehicle system could have been automatically controlled. Additionally, this manual operation and delay for trip plan generation can interfere with the schedules of other vehicle systems traveling on the same routes. For example, the trip plans for several vehicle systems traveling within and/or through the same transportation network during the same or overlapping time periods may be based on each other so as to avoid collision or other interferences between two or more moving vehicle systems. If one of the vehicle systems deviates from the trip plan of the vehicle system and is delayed during generation of a new or revised trip plan, then the trip plans of other vehicle systems may be interfered with by the vehicle system that deviates from the trip plan.